Gene Expression
The process of making RNA from DNA
Transcription
The enzyme that unwinds DNA during replication
helicase
This type of mutation changes a single nucleotide but does not alter the amino acid sequence.
a silent mutation
The diagram used to predict offspring genotypes
Punnett square
Small-scale changes within a population over time
Microevolution
The region where RNA polymerase binds to initiate transcription.
the promoter
The phase of mitosis where chromosomes line up at the equator
metaphase
A mutation that introduces a premature stop codon.
nonsense mutation
Traits influenced by multiple genes
Polygenic traits
The process where allele frequencies change due to chance
genetic drift
These non-coding sequences are removed during RNA processing.
introns
Crossing over occurs during this stage of meiosis
prophase I
This chromosomal abnormality involves extra or missing chromosomes
aneuploidy
The inheritance pattern where both alleles in a heterozygote are fully expressed.
codominance
The type of selection that favours extreme phenotypes
disruptive selection
The three-base sequence on mRNA that codes for an amino acid
a codon
These fragments are joined by ligase on the lagging strand
Okazaki fragments
This type of error during meiosis results in gametes with an abnormal number of chromosomes
Nondisjunction
If two heterozygous parents have a child, what is the probability the child will express the recessive trait?
25%
Speciation caused by geographic isolation
Allopatric speciation
This modification protects mRNA from degradation at its 3’ end
Poly-A tail
Name two sources of genetic variation in meiosis
crossing over and independent assortment
Explain how a frameshift mutation can affect the resulting protein.
it alters the reading frame, changing all downstream amino acids, often leading to a nonfunctional protein
Explain why males are more likely to express X-linked recessive traits than females.
because males have only one X chromosome, so a single recessive allele will be expressed
Explain how convergent evolution occurs
unrelated species evolve similar traits due to similar environments